During gas or oil well drilling an all-too-frequent occurrence is that drilling equipment becomes lost in the well. Because of the cost of new equipment, the time required to procure that new equipment and to set it in place, and the need to clear a well so that drilling can continue it is often advantageous to retrieve such lost equipment. The process of doing so is commonly known in the drilling industry as “fishing”.
A “fishing” expedition is performed by lowering one (1) or more equipment retrieval tools into the well. Equipment retrieval tools are designed to grasp or otherwise interact with the lost drilling equipment such that the equipment can be removed to enable continued drilling operations. A fishing expedition typically involves trying to couple one (1) or more retrieval tools to the lost drilling equipment, hopefully to enable both the retrieval tools and the lost drilling equipment to be removed from the well. Fishing operations should be understood as including the application of tools, equipment and techniques for the removal of junk, debris, tools and anything else left in a well bore.
One (1) common fishing tool is the overshot. An overshot is a well-drilling fishing tool that attaches to well tubing or pipe. An overshot is dropped down the well such that the overshot encompasses the outside walls of the drilling tube or pipe. Once the overshot is in place a basket grapple “grabs” the well tubing and allows the application of tensile forces and jarring actions such that the tubing can be pulled from the well. If the “fish” cannot be removed, a release system within the overshot allows the overshot to be disengaged and retrieved. As used herein “overshot” should be understood as having its customary meaning known to those skilled in drilling operations.
The assembly of fish equipment retrieval tooling is usually performed on the surface. Because of the nature of oil and gas well drilling it can be critical to perfectly align the equipment retrieval tooling to enable it to be dropped down a well to the lost equipment. Perfect alignment is easily said, but in practice it is far more difficult to accomplish in field conditions.
Accordingly, there exists a need for a system by which equipment retrieval tooling can be stabilized and carefully aligned. Preferably such alignment involves accurate vertical alignment such that a first section of the equipment retrieval tooling is vertically aligned with the second section, and then the third and subsequent sections. In addition, such as system should support proper rigging of fishing equipment as required for the well bore and equipment in issue. Such a system ideally should support safe, rapid assembly of the equipment retrieval tooling. Beneficially such a system should help reduce the chances of damage to the well, to the equipment retrieval tooling itself, and to the drilling equipment being recovered.